In many instances, thiamine hydrochloride is administered in solid dosage forms, typically of tablets, either singly or in combination with one or more other vitamins and/or some other drug or drugs.
These solid dosage forms are required to maintain their quality until administration. Therefore, thiamine hydrochloride should desirably be stabilized against heat and moisture. Commercially available grades of thiamine hydrochloride, which are mostly in the .alpha. form, are not always stable against heat or moisture absorption as desired. Therefore, in the prior art, measures have been taken to protect them from heat and moisture as much as possible for securing their quality.